Along with the development of network technology and a growing need of a user in services, terminals are gradually evolved to modularization, and a multimode terminal supports access to access networks of different types to bear diversified services. Different network connections have different characteristics and transmission capabilities, so that requirements of the user on multiple services and diversity can be better met. The multimode terminal can realize seamless connection between wireless access networks of different types, such as connection between a Universal Mobile Telecommunications System (UMTS)/Enhanced Data Rate for GSM Evolution (EDGE)/General Packet Radio Service (GPRS) and IEEE 802.11 WLAN. The WLAN can provide a high data rate in a small home and hotspot area, a cellular network can provide higher flexibility and a ubiquitous coverage but is low in data rate, and if the advantages of the WLAN and the cellular network can be combined, the user may be benefited. Within the coverage of a WLAN access point, the multimode terminal implements data access and Voice over Internet Protocol (VoIP) applications by virtue of the WLAN, and can also realize a voice call or media access by virtue of an overlay cellular network.
At present, the international standard organization Broadband Forum (BBF) and the 3GPP are executing the standard work of Fixed Mobile Convergence (FMC), and an involved scenario includes authentication, address allocation and policy control for the access of 3GPP User Equipment (UE) through a Residential Gateway (RG) from a BBF network. In an authentication process, the 3GPP UE initiates, as an 802.1x customer service side, access authentication to the RG, and then the RG initiates, as an 802.1x authenticator and an RADIUS (Remote Authentication Dial In User Service) customer service side, an authentication request to a BBF AAA (Authentication Authorization Accounting) server. In an address request process, the 3GPP UE initiates an address request message to a Packet Data Network Gateway (PDN-GW) for an IP address through a Broadband Network Gateway (BNG). An S2a session is established between the BNG and the PDN-GW, and is implemented through a GPRS Tunnelling Protocol (GTP) or Proxy Mobile IP (PMIP) tunnel.
In a relevant art, the BNG of each user needs to establish an S2a session with the PDN-GW. In order to support the scenario in an existing network, all BNG equipment is required to be upgraded, which causes greater influence on the existing network. In order to solve the problem, a Trusted WLAN Access Gateway (TWAG) (or called a BBF WLAN Access Gateway) is introduced, an FMC network structure after the TWAG is introduced is shown in FIG. 1. After the introduction of the TWAG, the BNG equipment is not required to be upgraded in a large scale, and influence on the existing network can be reduced as much as possible. However, no standard about how to apply the network after the introduction of the TWAG is not provided in the relevant art, and particularly, influence on the BNG and the BBF AAA server has not been taken into account.
Multiple methods for user address allocation under a TWAG introduction scenario have been provided in the relevant art, but there is yet no effective solution to problems about the guarantee of the Quality of Service (QoS) in the relevant art and network architecture.